Rotor assembly, permanent magnet synchronous motor, traction system, and vehicle

Abstract

Embodiments of the present application provide a rotor assembly, a permanent magnet synchronous motor, a traction system, and a vehicle. The rotor assembly comprises: a rotor core, having a plurality of permanent magnet slots uniformly distributed in the circumferential direction; permanent magnets, arranged in the permanent magnet slots; and a plurality of magnetic conductive blocks, arranged corresponding to the plurality of permanent magnet slots, each magnetic conductive block being radially arranged on the side of the corresponding permanent magnet slot close to a rotating shaft. The magnetic conductive block is configured to move between a first position close to the corresponding permanent magnet slot and a second position away from the corresponding permanent magnet slot, so as to adjust magnetic field distribution of the rotor assembly.

Description

Rotor assembly, permanent magnet synchronous motor, traction system and vehicle

[0001] Cross-reference to Related Applications

[0002] The present application is based on the Chinese patent application No. 202411262612.8, filed on September 10, 2024, entitled "Rotor assembly, permanent magnet synchronous motor, traction system and vehicle", and claims priority to the Chinese patent application, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of electric machines, and more particularly, to a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. BACKGROUND

[0004] With the rapid development of power electronics technology and high-performance rare earth materials, permanent magnet synchronous motors have been widely used for their high power density and high efficiency. The rotor of a permanent magnet synchronous motor is excited by a rare earth permanent magnet. Since the excitation magnetic field is not adjustable, and is limited by the DC bus voltage and the inverter capacity, when the system exceeds the rated power, as the speed rises, the back EMF of the stator winding rises. To ensure its operation at a higher speed, the rotor needs to be controlled for field weakening (also known as field regulation). The field regulation method in the related art includes AC pulse field regulation, DC pulse field regulation and mechanical field regulation.

[0005] The AC pulse field regulation is to apply a direct-axis magnetizing / demagnetizing pulse current through the stator armature winding to magnetize / demagnetize the permanent magnet, so as to adjust the air gap flux density and expand the operating speed of the motor.

[0006] The DC pulse field regulation is to additionally provide a DC field regulation winding on the motor stator or rotor for magnetizing / demagnetizing the permanent magnet.

[0007] The mechanical field regulation is to provide a plurality of slots in the rotor core, and to provide permanent magnets with the same polarity at both ends of the slots, wherein the outer side is fixed and the inner side is linked with a magnetic guide block to slide. When the motor speed rises, the permanent magnet linked with the magnetic guide block will move towards the air gap under the action of centrifugal force, so as to reduce the magnetic resistance of the main magnetic pole leakage path, increase the leakage magnetic flux, and reduce the magnetic flux through the air gap, so as to reduce the air gap flux density when the motor operates at high speed.

[0008] In the above various ways, the field weakening current during direct current or alternating current pulse magnet adjustment can cause high copper loss, which can cause the efficiency of the permanent magnet synchronous motor to decrease at high speed. Meanwhile, this method also requires additional components in the circuit part, resulting in an increase in cost. The existing mechanical magnet adjustment method is a passive adjustment, that is, the field weakening capability cannot be actively controlled. Moreover, the field weakening capability of this method is limited and cannot achieve the desired effect. SUMMARY

[0009] The present application mainly provides a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The various aspects related to the embodiments of the present application are introduced below.

[0010] In a first aspect, a rotor assembly is provided, comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; a plurality of permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each magnetic conductive block being arranged along a radial direction at a side of the corresponding permanent magnet slot close to a rotation shaft; the magnetic conductive block is configured to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot, so as to adjust the magnetic field distribution of the rotor assembly.

[0011] According to the above technical means, by arranging the magnetic conductive blocks corresponding to the plurality of permanent magnets in the rotor assembly, and adjusting the position of the magnetic conductive blocks to generate different leakage magnetic fields, the adjustment of the permanent magnet magnetic field is realized, the permanent magnet synchronous motor has a wider speed adjustment range, the power factor of the permanent magnet motor at high speed is improved, and the motor iron loss can be eliminated or reduced. When the magnetic conductive block moves to the end close to the permanent magnet, the rotor permanent magnet magnetic field can be concentrated in the rotor assembly, which can avoid the generation of a large counter electromotive force in the conductor when the motor is being towed, and ensure the safety of the traction system when the stator winding is short-circuited.

[0012] In some embodiments, when the magnetic conductive block is located at the first position, the end of the magnetic conductive block close to the permanent magnet slot abuts against the rotor core along the radial direction.

[0013] According to the above technical means, the end surface of the magnetic conductive block is completely coincident with the side wall of the rotor core, and there is no gap between the magnetic conductive block and the rotor core. The increase in magnetic resistance caused by the gap is avoided, and the permanent magnet magnetic field of the permanent magnet can be more concentrated in the magnetic conductive block.

[0014] In some embodiments, the permanent magnet slot comprises a first permanent magnet slot and a second permanent magnet slot symmetrically arranged about the D-axis center line; the first permanent magnet slot is close to one end of the rotating shaft and the second permanent magnet slot is close to one end of the rotating shaft to form a first opening, and the width of the magnetic conducting block along the direction perpendicular to the radial direction is not less than the width of the first opening, so that when the magnetic conducting block is in the first position, the end face of the magnetic conducting block close to one end of the permanent magnet slot can cover the first opening.

[0015] According to the above technical means, when the magnetic conducting block is in the first position, the material with high magnetic permeability occupies a large proportion in the core, which is more conducive to guiding the magnetic field into the magnetic conducting block.

[0016] In some embodiments, the rotor core has a recessed portion recessed towards the direction close to the permanent magnet slot, the recessed portion is arranged corresponding to the permanent magnet slot and located on the side of the permanent magnet slot close to the rotating shaft; the end of the magnetic conducting block close to the permanent magnet slot has a protruding portion, the shape of the protruding portion matches the shape of the recessed portion, and when the magnetic conducting block is in the first position, the protruding portion extends into the recessed portion.

[0017] According to the above technical means, by arranging the protruding portion extending towards the direction of the permanent magnet slot on the magnetic conducting block, when the magnetic conducting block moves to the first position, the permanent magnet magnetic field of the permanent magnet can be preferentially gathered in the magnetic conducting block with smaller magnetic resistance, thereby avoiding the part of the core from reaching the saturation state first.

[0018] In some embodiments, the protruding portion is a circular arc-shaped end face.

[0019] In some embodiments, the protruding portion comprises a first end face and a second end face arranged in a V shape, and the included angle formed by the first end face and the second end face is towards the end close to the permanent magnet slot.

[0020] According to the above technical means, the protruding portion is arranged in a V shape, which is simple in structure and easy to process.

[0021] In some embodiments, the included angle formed by the first end face and the second end face is an obtuse angle.

[0022] According to the above technical means, the included angle of the first end face and the second end face is arranged as an obtuse angle, so that the distance of the first end of the magnetic conducting block extending outward along the direction close to the permanent magnet slot will not be too long, thereby avoiding the problem that when the magnetic conducting block is in the second position, the air gap between the magnetic conducting block and the permanent magnet slot forms a magnetic barrier, affecting the distribution of the permanent magnet magnetic field of the rotor assembly, causing the efficiency of the motor to decrease, etc.

[0023] In some embodiments, the rotor core has a plurality of sliding grooves corresponding to a plurality of permanent magnet grooves, each of the sliding grooves is arranged along a radial direction, a first end of the sliding groove along the radial direction is close to the permanent magnet groove, and a second end of the sliding groove is arranged away from a rotating shaft of the rotor assembly, the magnetic conducting block is slidable in the sliding groove to move between the first position and the second position; the first end of the sliding groove has a recessed area matching the shape of the protruding part.

[0024] In some embodiments, an arc angle of the first permanent magnet groove and the second permanent magnet groove close to one end of the rotating shaft is less than or equal to an arc angle of the first permanent magnet groove and the second permanent magnet groove away from the one end of the rotating shaft.

[0025] According to the above technical means, the rotor structure with the V-shaped permanent magnet groove has the advantages of small magnetic leakage coefficient, no need to use magnetic isolation measures on the rotating shaft, easy to control the pole arc coefficient, high mechanical strength of the rotor lamination, and the rotor is not easy to deform after installation, and can be applied in many fields such as rail transit and electric vehicles.

[0026] In some embodiments, the first position is located close to one end of the first permanent magnet groove and the second permanent magnet groove close to the rotating shaft.

[0027] According to the above technical means, the first position is arranged close to the closed end of the V-shaped permanent magnet groove, which can achieve the effect of deep adjustment of the magnetic field, and will not increase the rotational inertia of the rotor too much, and can maintain high mechanical strength.

[0028] In some embodiments, the first permanent magnet groove is provided with a first magnetic isolation groove and a second magnetic isolation groove at two ends thereof, and the second permanent magnet groove is provided with a third magnetic isolation groove and a fourth magnetic isolation groove at two ends thereof.

[0029] According to the above technical means, the plurality of magnetic isolation grooves can avoid direct contact between two magnetic poles of the permanent magnet arranged in the permanent magnet groove and the rotor core.

[0030] In some embodiments, the rotor core further has an inner magnetic bridge corresponding to the permanent magnet groove, the inner magnetic bridge includes a first inner magnetic bridge and a second inner magnetic bridge, the first inner magnetic bridge is located between the sliding groove and the second magnetic isolation groove, and the second inner magnetic bridge is located between the sliding groove and the fourth magnetic isolation groove.

[0031] According to the above technical means, the first inner magnetic bridge and the second inner magnetic bridge can increase the structural strength of the rotor core.

[0032] In some embodiments, the rotor core further has an outer magnetic bridge corresponding to the permanent magnet slot, the outer magnetic bridge comprises a first outer magnetic bridge and a second outer magnetic bridge, the first outer magnetic bridge is located between the first magnetic isolation slot and the outer edge of the rotor assembly, and the second outer magnetic bridge is located between the third magnetic isolation slot and the outer edge of the rotor assembly.

[0033] According to the above technical means, the first outer magnetic bridge and the second outer magnetic bridge can increase the structural strength of the rotor core.

[0034] In some embodiments, the first magnetic isolation slot and the third magnetic isolation slot penetrate the rotor core in the radial direction.

[0035] According to the above technical means, the first magnetic isolation slot and the third magnetic isolation slot are arranged to penetrate the rotor core in the radial direction, which can reduce the magnetic leakage of the rotor permanent magnet and eliminate the adverse effects of the magnetic bridge on the magnetic field distribution.

[0036] In some embodiments, the rotor assembly further comprises a rotor sheath sleeved outside the rotor core.

[0037] According to the above technical means, the rotor sheath arranged outside the rotor core can improve the strength of the rotor assembly.

[0038] In some embodiments, the rotor sheath is made of carbon fiber or non-magnetic alloy material.

[0039] According to the above technical means, the rotor sheath is made of carbon fiber or non-magnetic alloy material, which can meet the strength requirements and will not affect the magnetic field distribution of the rotor assembly.

[0040] In some embodiments, the rotor assembly further comprises a driving mechanism for driving the magnetic conductive block to move.

[0041] In some embodiments, the rotor core comprises a core shaft core, a D-axis core and a Q-axis core; wherein the core shaft core is a shaft sleeve close to the shaft center of the rotor core; the D-axis core is located between the first permanent magnet slot and the second permanent magnet slot; and the Q-axis core is located between two adjacent permanent magnet slots.

[0042] In some embodiments, the core shaft core, the D-axis core and the Q-axis core are integrally formed.

[0043] According to the above technical means, the integrally formed rotor core has simple process and can reduce the processing cost of the rotor core.

[0044] In some embodiments, the shaft core, the D-axis core and the Q-axis core are combined structures; the D-axis core is made of silicon steel material, amorphous material or nanocrystalline material; and the Q-axis core is made of silicon steel material, amorphous material or nanocrystalline material.

[0045] According to the above technical means, the D-axis core is made of silicon steel material, amorphous material or nanocrystalline material, which has small iron loss and can reduce the heat generation of the rotor core; and the Q-axis core is made of silicon steel material, amorphous material or nanocrystalline material, the orientation direction of the silicon steel material is axial and has high permeability; and the nanocrystalline material also has high permeability, which can reduce the heat generation of the rotor assembly while realizing the miniaturization and light weight of the motor.

[0046] In some embodiments, the shaft core and the Q-axis core are integrally formed, or the Q-axis core and the shaft core are connected through a dovetail structure.

[0047] According to the above technical means, the shaft core and the Q-axis core are integrally formed and can be made of the same material, which can reduce the processing procedures. The Q-axis core and the shaft core are connected through a dovetail structure, which can greatly improve the material utilization rate and save the manufacturing cost.

[0048] In a second aspect, a permanent magnet synchronous motor is provided, including a rotor assembly and a stator assembly, the rotor assembly being the rotor assembly of the first aspect.

[0049] In a third aspect, a permanent magnet synchronous motor is provided, which is applied to a power system of a city rail transit vehicle, the vehicle power system including a plurality of permanent magnet synchronous motors for providing power for the vehicle, the permanent magnet synchronous motor including a rotor assembly and a stator assembly, the rotor assembly including: a rotor core having a plurality of permanent magnet slots uniformly distributed along the circumference; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being arranged on the side close to the rotation shaft of the corresponding permanent magnet slot along the radial direction; the magnetic conductive blocks are configured to: when the vehicle is in an idle condition, the magnetic conductive blocks are located at a first position close to the permanent magnet slots to reduce the iron loss of the permanent magnet synchronous motor in the idle condition; and when the vehicle is in a traction condition, the magnetic conductive blocks are located at a second position away from the permanent magnet slots to increase the air gap magnetic field strength between the rotor assembly and the stator assembly.

[0050] In some embodiments, the magnetic conductive blocks are further configured to: when the speed of the vehicle is greater than a first speed threshold, the magnetic conductive blocks move between the first position and the second position to adjust the magnetic field distribution of the rotor assembly and increase the speed regulation range of the permanent magnet synchronous motor; wherein the first speed threshold is related to the rated speed of the permanent magnet synchronous motor.

[0051] In a fourth aspect, there is provided a power system for a rail transit vehicle, configured to provide power for the rail transit vehicle, the power system comprising the permanent magnet synchronous motor of the third aspect.

[0052] In a fifth aspect, there is provided a rail transit vehicle, the rail transit vehicle comprising the permanent magnet synchronous motor of the third aspect or the power system of the fourth aspect.

[0053] In a sixth aspect, there is provided a permanent magnet synchronous traction motor for a traction system of a locomotive, the permanent magnet synchronous traction motor comprising a rotor assembly and a stator assembly, the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; a plurality of permanent magnets arranged in the plurality of permanent magnet slots; and a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the plurality of magnetic conductive blocks being arranged at a side of a corresponding permanent magnet slot close to a rotation axis along a radial direction, the plurality of magnetic conductive blocks being configured to move between a first position close to the corresponding permanent magnet slot and a second position away from the corresponding permanent magnet slot according to a running speed of the locomotive, to adjust a magnetic field distribution of the rotor assembly, so that the permanent magnet synchronous traction motor outputs a constant power when driving the locomotive to operate within a range of the running speed.

[0054] In some embodiments, the plurality of magnetic conductive blocks are further configured to be located at or close to the first position to reduce an air gap magnetic field strength of the rotor assembly and increase a rotation speed of the permanent magnet synchronous traction motor when the speed of the locomotive is greater than a first speed, the first speed being related to a rated rotation speed of the permanent magnet synchronous traction motor.

[0055] In a seventh aspect, there is provided a traction system for a locomotive, the traction system comprising the permanent magnet synchronous traction motor of the sixth aspect.

[0056] In an eighth aspect, there is provided a locomotive comprising the permanent magnet synchronous traction motor of the sixth aspect or the traction system of the seventh aspect.

[0057] In a ninth aspect, a power system is provided for a train, the power system comprising a plurality of permanent magnet synchronous machines for driving the train to run, each of the permanent magnet synchronous machines comprising a rotor assembly and a stator assembly; the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being arranged along a radial direction at a side of a corresponding permanent magnet slot close to a rotation shaft, the magnetic conductive blocks being configured to switch between a first position close to the permanent magnet slots and a second position away from the permanent magnet slots to adjust a magnetic field distribution of the rotor assembly; and the power system being configured to: in a case where a target permanent magnet synchronous machine of the plurality of permanent magnet synchronous machines has an inter-turn short circuit fault, switch the magnetic conductive blocks in the target permanent magnet synchronous machine to the first position to short-circuit a main magnetic flux of the target permanent magnet synchronous machine, and make the target permanent magnet synchronous machine exit service.

[0058] In a tenth aspect, a train is provided, comprising the power system of the ninth aspect.

[0059] In an eleventh aspect, a permanent magnet synchronous machine is provided for a mobile equipment, the permanent magnet synchronous machine comprising a stator assembly and a rotor assembly, the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being arranged along a radial direction at a side of a corresponding permanent magnet slot close to a rotation shaft, the magnetic conductive blocks being configured to move between a first position close to the permanent magnet slots and a second position away from the permanent magnet slots to adjust a magnetic field distribution of the rotor assembly; and the magnetic conductive blocks being configured to: when a speed of the mobile equipment is greater than a first speed, move to or close to the first position to improve an efficiency of the permanent magnet synchronous machine in a high-speed working condition.

[0060] In a twelfth aspect, a mobile equipment is provided, comprising the permanent magnet synchronous machine of the eleventh aspect.

[0061] In a thirteenth aspect, a permanent magnet synchronous machine is provided, comprising a stator assembly and a rotor assembly, the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being arranged along a radial direction at a side of a corresponding permanent magnet slot close to a rotation shaft, the magnetic conductive blocks being configured to move between a first position close to the permanent magnet slots and a second position away from the permanent magnet slots to adjust a magnetic field distribution of the rotor assembly; and the magnetic conductive blocks being further configured to: when a back electromotive force of the stator assembly increases, move from the second position to a direction close to the first position to reduce the back electromotive force of the stator assembly.

[0062] In a fourteenth aspect, a vehicle is provided, comprising the permanent magnet synchronous motor according to the thirteenth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0063] FIG. 1 is a structural schematic diagram of a rotor assembly according to an embodiment of the present application;

[0064] FIG. 2 is a simulation result of magnetic field distribution of the rotor assembly in FIG. 1;

[0065] FIG. 3 is a structural schematic diagram of a rotor assembly according to another embodiment of the present application;

[0066] FIG. 4 is a simulation result of magnetic field distribution of the rotor assembly in FIG. 3;

[0067] FIG. 5 is a schematic diagram of a fixed magnetic bridge in a rotor core according to an embodiment of the present application;

[0068] FIG. 6 is a schematic diagram of a fixed magnetic bridge in a rotor core according to another embodiment of the present application;

[0069] FIG. 7 is a structural schematic diagram of a rotor assembly in the related art;

[0070] FIG. 8 is a simulation result of magnetic field distribution of the rotor assembly in FIG. 7;

[0071] FIG. 9 is a structural schematic diagram of a rotor core according to an embodiment of the present application. DETAILED DESCRIPTION

[0072] Embodiments of the present application provide a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The technical solutions of the present application will be further specifically explained below by embodiments and in conjunction with the drawings. In the description, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present application is intended to explain the general concept of the present application, and should not be understood as a limitation of the present application.

[0073] Before introducing the technical solutions provided by the embodiments of the present application, the permanent magnet synchronous motor in the related art and the problems thereof will be described in detail.

[0074] A permanent magnet synchronous motor (PMSM) mainly comprises a stator assembly, a rotor assembly and a motor shell and the like. The stator assembly comprises a stator core and a stator winding wound thereon. When three-phase current is supplied to the stator winding, a rotating magnetic field is generated, which interacts with a permanent magnetic field excited by a permanent magnet in the rotor assembly to provide torque for the rotor assembly.

[0075] Permanent magnet motor has a series of advantages such as small size, low weight, high power density, etc. It can output larger torque at low speed and has excellent low-speed performance. Meanwhile, China is rich in rare earth mineral resources, and the manufacturing cost of permanent magnet synchronous motor is relatively low. This makes the permanent magnet synchronous motor widely used in electric vehicles, high-speed railways, urban rail transit, aerospace and industrial production, etc.

[0076] However, permanent magnet synchronous motor also faces some practical problems in engineering applications, which are described below.

[0077] The air gap magnetic field of the permanent magnet synchronous motor is difficult to adjust, resulting in a narrow constant power region. In order to solve this problem, the method of field weakening control (also known as flux regulation) can be used to expand the speed.

[0078] The motor flux regulation method in the related art includes AC pulse flux regulation, DC pulse flux regulation and mechanical flux regulation.

[0079] Among them, the AC pulse flux regulation method is to apply direct-axis magnetizing / demagnetizing pulse current through the stator armature winding to realize the magnetization / demagnetization of the permanent magnet, so as to adjust the air gap flux density and expand the operation of the motor.

[0080] The DC pulse flux regulation method is to additionally set a DC flux regulation winding on the motor stator or rotor for magnetizing / demagnetizing the permanent magnet.

[0081] The mechanical flux regulation method is to change the magnetic field distribution of the motor main magnetic circuit by adding a mechanical mechanism in the stator or rotor, so as to adjust the air gap flux density of the motor. The mechanical structure may, for example, be a plurality of slots provided in the rotor core, and permanent magnets with the same polarity are provided at both ends of the slots, wherein the outer side is fixed and the inner side is linked with a magnetic block that slides. When the motor speed increases, the permanent magnet linked with the magnetic block will move towards the air gap under the action of centrifugal force, so that the magnetic resistance of the main magnetic pole leakage path decreases, the leakage magnetic flux increases, and the magnetic flux through the air gap decreases, thereby achieving the purpose of reducing the air gap flux density when the motor runs at high speed.

[0082] In the above-mentioned various methods, the field weakening current during DC or AC pulse flux regulation will cause high copper loss, which will reduce the efficiency of the permanent magnet synchronous motor at high speed. At the same time, this method also needs to add additional components in the circuit part, resulting in an increase in cost. The existing mechanical flux regulation method is a passive adjustment, i.e. it cannot actively control the field weakening capability, and the field weakening capability of this method is limited and cannot achieve the expected effect.

[0083] In addition, in some special scenarios, for example, for application to rail transit vehicles such as high-speed railways, when a motor turn short fault occurs when the train is running at high speed, the motor stator three-phase winding is cut off and the rotor is idling under external force. In this case, the winding coil continuously cuts the permanent magnet magnetic field, generating a large induced electromotive force, resulting in a large circulating current in the shorted coil. This current will cause the winding to heat up and even catch fire on the one hand, and the large short-circuit current will generate a pulsating magnetic field, which will interact with the rotor permanent magnet magnetic field to cause the rotor to vibrate, directly endangering the safe operation of the vehicle. At this time, if the permanent magnet magnetic flux of the rotor can be adjusted to 0 or close to 0, there will be no induced electromotive force in the three-phase winding coil, thereby ensuring the safety of driving.

[0084] Therefore, how to further adjust the permanent magnet magnetic field of the rotor of the permanent magnet synchronous motor has become a problem to be solved.

[0085] In view of the above problems, the embodiments of the present application provide a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. The technical solutions of the embodiments of the present application will be described in detail below with reference to the drawings.

[0086] FIG. 1 is a schematic structural diagram of a rotor assembly 10 provided by the embodiments of the present application, which includes a rotor core 11, a permanent magnet 12 and a magnetic conducting block 13.

[0087] The rotor core 11 has a plurality of permanent magnet grooves 111 uniformly distributed along the circumferential direction.

[0088] The circumferential direction mentioned in the embodiments of the present application refers to the circumferential direction around the axial direction of the rotor core 11, and the axial direction refers to the direction of the central axis of the rotor core 11.

[0089] The permanent magnet 12 is arranged in the permanent magnet groove 111.

[0090] The permanent magnet mentioned in the embodiments of the present application refers to a magnet capable of maintaining magnetism for a long time, such as natural magnetite (ferromagnetic ore) and artificial magnetic steel (for example, iron-nickel-cobalt magnetic steel, neodymium-iron-boron magnetic steel and samarium-cobalt magnetic steel, etc.).

[0091] The magnetic conducting block 13 is arranged corresponding to the permanent magnet groove 111, and each magnetic conducting block 13 is arranged on the side close to the shaft of the corresponding permanent magnet groove 111 along the radial direction.

[0092] The magnetic conducting block 13 is configured to move between a first position close to the permanent magnet groove 111 and a second position away from the permanent magnet groove 111, so as to adjust the magnetic field distribution of the rotor assembly 10.

[0093] According to the principle of minimum reluctance, the magnetic field will be distributed along the direction of smaller reluctance, and the magnetic reluctance of the magnetic conductive block 13 is much smaller than air. Therefore, in the rotor assembly 10, the magnetic flux lines of the permanent magnet magnetic field generated by the permanent magnet 12 will preferentially pass through the magnetic conductive block; when the position of the magnetic conductive block 13 changes, the magnetic field distribution in the rotor assembly 10 changes accordingly.

[0094] More specifically, when the magnetic conductive block 13 is located at the first position close to the permanent magnet slot 111, the rotor permanent magnet magnetic field will gather to the position of the magnetic conductive block 13; or in other words, in the case that the magnetic conductive block is located at the first position close to the permanent magnet slot 111, the rotor permanent magnet magnetic field does not pass through the air gap of the rotor assembly; or in other words, in the case that the magnetic conductive block is located at the first position close to the permanent magnet slot 111, the air gap magnetic field of the rotor assembly is 0.

[0095] When the magnetic conductive block 13 is located at the second position away from the permanent magnet slot 111, an air gap is formed between the magnetic conductive block 13 and the rotor core 11, and the magnetic reluctance at this position is larger. The permanent magnet magnetic field of the permanent magnet 12 will preferentially pass through the rotor core with smaller magnetic reluctance, and at this time the magnetic field strength of the air gap magnetic field of the rotor assembly 10 is larger.

[0096] In some embodiments, the magnetic conductive block 13 is made of a material with high saturation magnetic induction, for example, 1J22 alloy, which has a saturation magnetic induction of 2.4T or higher, much larger than the saturation magnetic induction of air and silicon steel sheet. The magnetic conductive block made of a material with high saturation magnetic induction can meet the requirement of adjusting the magnetic flux of the rotor assembly to the maximum in the minimum size.

[0097] In some embodiments, when the magnetic conductive block 13 is located at the first position, the end of the magnetic conductive block 13 close to one end of the permanent magnet slot 111 abuts against the rotor core 11 along the radial direction.

[0098] That is, in the above state, the end surface of the magnetic conductive block 13 is completely coincident with the side wall of the rotor core 11, and there is no gap between the magnetic conductive block 13 and the rotor core 11; if there is a gap, it will cause the magnetic reluctance at this position to be larger, and it cannot be ensured that the permanent magnet magnetic field of the permanent magnet can be more concentrated in the magnetic conductive block.

[0099] In some embodiments, as shown in FIGS. 1 and 3, the permanent magnet slot 111 includes a first permanent magnet slot 1111 and a second permanent magnet slot 1112. The first permanent magnet slot 1111 and the second permanent magnet slot 1112 are symmetrically arranged about the D-axis center line. The plurality of first permanent magnet slots 1111 and second permanent magnet slots 1112 in the rotor assembly 10 are alternately arranged and radially arranged.

[0100] The first permanent magnet slot 1111 and the second permanent magnet slot 1112 form a first opening at one end close to the rotating shaft, and the width of the magnetic conductive block 13 along the direction perpendicular to the radial direction is not less than the width of the first opening, so that the end face of the magnetic conductive block 13 close to the one end of the permanent magnet slot 111 can completely cover the first opening, so that when the magnetic conductive block 13 is located at the first position, the proportion of the material with high magnetic conductivity in the iron core is large, which is more conducive to guiding the magnetic field into the magnetic conductive block 13.

[0101] In some embodiments, the rotor iron core 11 has a recess 112 recessed towards the direction close to the permanent magnet slot 111, the recess 112 is arranged corresponding to the permanent magnet slot 111 and located at the side of the permanent magnet slot 111 close to the rotating shaft.

[0102] Correspondingly, the one end of the magnetic conductive block 13 close to the permanent magnet slot 111 has a protruding portion, which matches the shape of the recess 112, and when the magnetic conductive block 13 is located at the first position, the protruding portion extends into the recess 112.

[0103] By arranging the protruding portion extending towards the direction of the permanent magnet slot on the magnetic conductive block 13, when the magnetic conductive block moves to the first position, the permanent magnet magnetic field of the permanent magnet can be preferentially gathered in the magnetic conductive block with smaller magnetic resistance, thereby avoiding the iron core part from reaching the saturation state first.

[0104] In some embodiments, as shown in FIG. 1, the first end of the magnetic conductive block 13 has a first end face 131 and a second end face 132, the first end face 131 and the second end face 132 form an included angle, and the included angle is towards the one end close to the permanent magnet slot 111. In other words, the first end face 131 and the second end face 132 form the protruding portion of the magnetic conductive block 13. The protruding portion is arranged in a V shape, which is simple in structure and easy to process.

[0105] It should be noted that the distance of the first end of the magnetic conductive block 13 extending outward along the direction close to the permanent magnet slot 111 should not be too long. For example, when the included angle of the first end face 131 and the second end face 132 in FIG. 1 is small, since the recess 112 matches the shape of the magnetic conductive block 13, an air gap will be formed in the permanent magnet slot 111 at this time, and when the magnetic conductive block 13 is located at the second position, the above-mentioned air gap will form a magnetic barrier, affecting the adjustment of the permanent magnet magnetic field of the rotor assembly.

[0106] Therefore, in the embodiments of the present application, the included angle between the first end face 131 and the second end face 132 is obtuse.

[0107] Of course, the shape of the protruding portion is not limited to the form in FIG. 1, and can also be a circular arc, a rectangle, and a polygon (such as a trapezoid).

[0108] In some embodiments, the rotor core 11 has a plurality of sliding grooves 113 corresponding to the plurality of permanent magnet grooves 111. Each sliding groove 113 is arranged along a radial direction, and a first end of each sliding groove 113 along the radial direction is close to the permanent magnet groove 111, and a second end is spaced apart from the rotation shaft of the rotor assembly 10. The magnetic conducting block 13 can move in the sliding groove 113 to move between the first position and the second position.

[0109] It should be understood that the radial direction herein can be understood as a direction perpendicular to the aforementioned axial direction.

[0110] The first end of the sliding groove 113 has a recessed area 1131 which matches the shape of the protruding part of the magnetic conducting block 13. Alternatively, the recessed area 1131 forms the recessed part 112 described above.

[0111] Of course, the shape of the first end of the sliding groove 113 is not limited to the form in FIG. 1, and the first end of the sliding groove 113 can also be circular arc-shaped, rectangular, polygonal (e.g., trapezoidal), etc., as long as the shape of the magnetic conducting block 13 can match it.

[0112] The technical solution will be further described below in combination with FIGS. 1-4. In FIG. 1, the plurality of magnetic conducting blocks 13 are all located at the second position away from the permanent magnet groove, and the magnetic field distribution at this time is shown in FIG. 2; in FIG. 3, the plurality of magnetic conducting blocks are all located at the first position close to the permanent magnet groove, and the magnetic field distribution at this time is shown in FIG. 4.

[0113] It should be noted that, for the convenience of understanding, only part of the rotor assembly 10 and the corresponding stator assembly are shown in FIGS. 2 and 4. In FIGS. 2 and 4, the closer the color is to orange, the higher the magnetic field strength is, and the closer the color is to blue, the lower the magnetic field strength is.

[0114] When the magnetic conducting block 13 is located at the second position as shown in FIG. 1, it can be seen from FIG. 2 that the magnetic field strength in the air gap between the magnetic conducting block 13 and the rotor core is close to 0, and the magnetic induction lines of the permanent magnet field of the permanent magnet mostly extend outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly, especially at the end of the core of the stator assembly.

[0115] When the magnetic conducting block 13 is located at the first position as shown in FIG. 3, it can be seen from FIG. 4 that the magnetic induction lines of the permanent magnet field of the permanent magnet mostly extend to the position of the magnetic conducting block 13, i.e., the permanent magnet field is gathered to the side away from the air gap, and the magnetic field strength at the position of the magnetic conducting block is the maximum, while the magnetic field strength in the air gap is 0.

[0116] It can be understood that the magnetic field distribution of the magnetic conducting block 13 is only shown in the two extreme positions of the first position and the second position in FIGS. 1-4, and in actual application, the magnetic conducting block 13 can be arranged at any position between the first position and the second position according to the needs of specific scenes. When the magnetic conducting block 13 is in different positions, the rotor assembly can present different air gap magnetic fields.

[0117] According to the above technical solutions provided by the embodiments of the present application, by arranging the magnetic conducting block corresponding to the plurality of permanent magnet groups in the rotor assembly, and adjusting the position of the magnetic conducting block to generate different leakage magnetic fields, the adjustment of the permanent magnet magnetic field is realized, the speed regulation range of the permanent magnet synchronous motor is ensured to be wide, the power factor of the permanent magnet motor at high speed is improved, and the motor idle running iron loss can be eliminated or reduced. When the magnetic conducting block is moved to the end close to the permanent magnet, the rotor permanent magnet magnetic field can be concentrated in the rotor assembly, which can avoid a large circulating current generated by the motor when it is being towed, and ensure the safety of the traction system when the turns of the stator winding are short-circuited.

[0118] When it is applied to the permanent magnet traction system of a railway train, by adjusting the position of the magnetic conducting block, the magnetic field can not pass through the air gap at all, so that the motor will not generate circulating current in the stator winding due to the induction of potential in the case of turn-to-turn short circuit fault, and the fault-oriented safety of the permanent magnet traction motor is ensured; when the vehicle is inert, the generation of iron loss of the motor can also be avoided by eliminating the magnetic field; when the vehicle is running at high speed, the leakage magnetic quantity at the magnetic conducting block can be adjusted by adjusting the position of the magnetic conducting block, so as to adjust the main magnetic field, expand the speed regulation range of the motor, and make the motor have higher power factor and efficiency under high-speed working condition. The technical solution can completely solve the pain points of the permanent magnet traction system, improve the efficiency, solve the safety problem, and has great significance for the safe operation of the next generation of permanent magnet traction system.

[0119] In some embodiments, as shown in FIGS. 1 and 3, the first permanent magnet slot 1111 and the second permanent magnet slot 1112 close to the end of the rotating shaft have an arc angle smaller than or equal to the arc angle away from the end of the rotating shaft. In other words, the first permanent magnet slot 1111 and the second permanent magnet slot 1112 in the same permanent magnet slot 111 are arranged in a V shape.

[0120] It should be noted that the first permanent magnet slot 1111 and the second permanent magnet slot 1112 close to the end of the rotating shaft are not connected to each other. The above-mentioned rotor structure with V-shaped permanent magnet slots has the advantages of small leakage magnetic coefficient, no need to use magnetic isolation measures on the rotating shaft, easy control of pole arc coefficient, high mechanical strength of rotor lamination, and no deformation of the rotor after installation, and can be applied in many fields such as rail transit and electric vehicles.

[0121] In some embodiments, the first position is located at one end of the first permanent magnet slot 1111 and the second permanent magnet slot 1112 close to the rotation shaft. Alternatively, the first end of the sliding slot 113 is close to the closed end of the V-shaped permanent magnet slot. In this way, the depth of the magnetic field can be adjusted, and the rotational inertia of the rotor can be increased, and the mechanical strength can be maintained.

[0122] In some embodiments, as shown in FIGS. 5 and 6, the first permanent magnet slot 1111 is provided with a first magnetic isolation slot 1111a and a second magnetic isolation slot 1111b at both ends, and the second permanent magnet slot 1112 is provided with a third magnetic isolation slot 1112a and a fourth magnetic isolation slot 1112b at both ends. The purpose of the above-mentioned multiple magnetic isolation slots is to avoid the leakage of the two magnetic poles of the permanent magnet arranged in the permanent magnet slot.

[0123] In some embodiments, the second magnetic isolation slot 1111b and the fourth magnetic isolation slot 1112b are in communication with the sliding slot 113, and the structure of the rotor assembly can be referred to FIGS. 1 and 3.

[0124] In some embodiments, as shown in FIGS. 5 and 6, the rotor core 11 further has an outer magnetic bridge 114 corresponding to the permanent magnet slot 111. More specifically, the outer magnetic bridge 114 includes a first outer magnetic bridge 114a and a second outer magnetic bridge 114b. The first outer magnetic bridge 114a is arranged between the first magnetic isolation slot 1111a and the outer edge of the rotor assembly 10, and the second outer magnetic bridge 114b is arranged between the third magnetic isolation slot 1112a and the outer edge of the rotor assembly 10. It should be noted that FIGS. 5 and 6 respectively show the case that the magnetic conducting block 13 is located at both ends of the sliding slot 113.

[0125] In some embodiments, as shown in FIGS. 5 and 6, the rotor core 11 further has an inner magnetic bridge 115 corresponding to the permanent magnet slot 111. More specifically, the inner magnetic bridge 115 includes a first inner magnetic bridge 115a and a second inner magnetic bridge 115b. The first inner magnetic bridge 115a is arranged between the sliding slot 113 and the second magnetic isolation slot 1111b, and the second inner magnetic bridge 115b is arranged between the sliding slot 113 and the fourth magnetic isolation slot 1112b.

[0126] The main purpose of arranging the first outer magnetic bridge 114a and the second outer magnetic bridge 114b is to increase the structural strength of the rotor core 11. However, the existence of the outer magnetic bridge will cause the leakage of the rotor permanent magnet, which will increase the consumption of the permanent magnet.

[0127] The following will be described in conjunction with an example. FIGS. 7 and 8 show the simulation diagram of the rotor assembly and the magnetic field distribution in the related art.

[0128] As shown in FIG. 7, the rotor assembly 30 is provided with a first permanent magnet slot 31a and a second permanent magnet slot 31b, and a first magnetic isolation slot 32a and a second magnetic isolation slot 32b are respectively arranged at two ends of the first permanent magnet slot 31a, and a third magnetic isolation slot 33a and a fourth magnetic isolation slot 33b are respectively arranged at two ends of the second permanent magnet slot 31b. The first magnetic isolation slot 32a and the third magnetic isolation slot 33a are connected with edges of the rotor assembly, and a first outer magnetic bridge 34a and a second outer magnetic bridge 34b are arranged between the first magnetic isolation slot 32a and the third magnetic isolation slot 33a. The rotor assembly 30 is further provided with a magnetic isolation hole 35, and a first inner magnetic bridge 36a and a second inner magnetic bridge 36b are respectively arranged between the magnetic isolation hole 35 and the second magnetic isolation slot 32b and the fourth magnetic isolation slot 33b.

[0129] As can be seen from the simulation result of FIG. 8, the permanent magnets first saturate the outer magnetic bridge 35 and the inner magnetic bridge 36, the magnetic field strength is larger near the magnetic bridge, and part of the permanent magnets does not participate in the establishment of the main magnetic flux, which is an invalid part.

[0130] In view of the above problems, in order to eliminate the adverse effects of the magnetic bridge on the magnetic field distribution, in some embodiments, the first magnetic isolation slot 1111a and the third magnetic isolation slot 1112a penetrate the rotor core 11 along the radial direction; that is, in this embodiment, there is no outer magnetic bridge on the rotor core 11, and the structure of the rotor assembly can refer to FIGS. 1 and 3.

[0131] In the foregoing embodiments, since the permanent magnet slot 111 penetrates the outer edge of the rotor core 11 through the magnetic isolation slot, when the rotor assembly 10 rotates at high speed, the rotor core and the permanent magnets will bear a large centrifugal force.

[0132] Therefore, in order to ensure the structural strength of the rotor assembly 10, in some embodiments, as shown in FIGS. 1 and 3, the rotor assembly 10 is further provided with a rotor sheath 15, which is sleeved outside the rotor core 11, for improving the strength of the rotor assembly.

[0133] In some embodiments, the rotor sheath 15 is made of carbon fiber or non-magnetic alloy material, which can meet the demand for strength and will not affect the magnetic field distribution of the rotor assembly. By reducing the outer magnetic bridge, the air gap width can be increased, which is also beneficial to reducing the magnetic leakage on the side of the magnetic conductive block.

[0134] In some embodiments, as shown in FIG. 9, the rotor core 11 includes a core shaft core 11a, a D-axis core 11b and a Q-axis core 11c. The core shaft core 11a is a shaft sleeve close to the axis of the rotor core 11, the D-axis core 11b is located between the first permanent magnet slot 1111 and the second permanent magnet slot 1112, and the Q-axis core 11c is located between two adjacent permanent magnet slots 111.

[0135] It should be noted that the dashed line in FIG. 9 is for the convenience of describing and understanding each part in the rotor core 11, and does not mean that the shaft core 11a, the D-axis core 11b and the Q-axis core 11c are separated from each other.

[0136] In some embodiments, the shaft core 11a, the D-axis core 11b and the Q-axis core 11c are integrally formed. The integrally formed manner is simple in process and can reduce the processing cost of the rotor core.

[0137] In some embodiments, the shaft core 11a, the D-axis core 11b and the Q-axis core 11c are combined structures, which can be made of different materials.

[0138] The D-axis core 11b is made of silicon steel material, amorphous material or nanocrystalline material. The iron loss of such materials is small, which can reduce the heating of the rotor core.

[0139] The Q-axis core 11c is made of silicon steel material, amorphous material or nanocrystalline material. The orientation direction of the silicon steel material is axial and has high magnetic permeability; the nanocrystalline material also has high magnetic permeability, which can reduce the heating of the rotor assembly while realizing the miniaturization and light weight of the motor.

[0140] In some embodiments, the shaft core 11a and the Q-axis core 11c are integrally formed, which can be made of the same material and can reduce the processing procedure.

[0141] In some embodiments, the shaft core 11a and the Q-axis core 11c can be connected by a dovetail structure. Specifically, the shaft core 11a is a sleeve structure, and a plurality of dovetail grooves are distributed on the outer surface of the sleeve structure in the axial direction. The Q-axis core 11c is provided with a dovetail-shaped protrusion at one end close to the shaft core 11a, which is inserted into the dovetail groove of the shaft core 11a to combine the Q-axis core 11c and the shaft core 11a. Compared with the integrally formed manner of the shaft and the Q-axis core, this technical solution can greatly improve the utilization rate of materials and save manufacturing costs.

[0142] In some embodiments, the rotor assembly 10 further comprises a driving mechanism to drive the magnetic block 13 to move in the chute 113.

[0143] The embodiment of the present application provides a permanent magnet synchronous motor, which comprises a rotor assembly and a stator assembly, wherein the rotor assembly is the rotor assembly described in any of the preceding embodiments.

[0144] The permanent magnet synchronous motor can be applied in various fields such as aviation, national defense, industrial and agricultural production and daily life. Specifically, the motor can be applied to industrial driving devices, automation equipment, fans, pumps, compressors, machine tools, robots and vehicles.

[0145] The vehicle can include a road vehicle, an air vehicle, a water vehicle, an industrial device, an agricultural device, an entertainment device, or the like.

[0146] The water vehicle can be a hovercraft, a speedboat, a motorboat, a fishing boat, a cruise ship, a sailboat, a yacht, or the like.

[0147] The air vehicle can be an airplane, and the road vehicle can be a vehicle.

[0148] In some embodiments, the vehicle is a vehicle. The vehicle can be one of a commercial vehicle, a passenger vehicle, a motorcycle, a flying vehicle, a train, or the like.

[0149] In some embodiments, the vehicle is an industrial vehicle or an engineering vehicle. The vehicle can be one of a forklift, a trailer, a tractor, an excavator, a bulldozer, a crane, or the like.

[0150] In some embodiments, the vehicle can be an electric vehicle or a fuel vehicle. The vehicle can be one of a pure electric vehicle (PEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), and a plug-in hybrid electric vehicle (PHEV).

[0151] In some embodiments, the vehicle can also be an agricultural device (such as a mower, a harvester, or the like), a recreational device, a toy vehicle, or the like.

[0152] In some embodiments, the vehicle can also be a high-speed railway train, a motor train unit, a city rail transit vehicle, or the like.

[0153] The embodiments of the present application also provide a permanent magnet synchronous motor, a power system, and a city rail transit vehicle.

[0154] The total energy consumption of the city rail transit system can be divided into station operation energy consumption and train operation energy consumption. The station operation energy consumption includes energy consumption of station lighting, air conditioning, elevators, and the like, and the energy consumption value is relatively fixed and the proportion of the overall energy consumption is small. The vehicle energy consumption is mainly the traction energy consumption in the train operation process. The traction motor is an important part of the traction system for energy conversion, and improving its efficiency in various working conditions is an important measure to reduce the train energy consumption.

[0155] The distance between stations of urban rail system is usually short, and the running process of a vehicle between two stations includes three sections of acceleration, coasting and deceleration. The vehicle starts from static state and accelerates to the highest speed when leaving a station, and then coasts for a distance, and starts to brake until stopping when approaching the next station. Alternatively, when the distance between stations is long, the vehicle can experience a second acceleration section and a second coasting section after the first coasting section, i.e., the vehicle accelerates twice after coasting. That is, the power system of such a vehicle needs to start and stop frequently, and the coasting condition occurs frequently.

[0156] From the demand of urban rail vehicles for traction electric drive system, in order to improve the running efficiency, the urban rail vehicle needs to have as large as possible acceleration / deceleration in the acceleration and deceleration sections, which requires a large torque in the starting and braking stages.

[0157] At present, asynchronous induction motor is widely used as the driving motor of urban rail vehicle. The asynchronous induction motor provides excitation magnetic field by rotor winding, and generates rotating magnetic field when three-phase current is applied to the stator winding, and the rotating magnetic field interacts with the excitation magnetic field of the rotor winding to provide torque for the rotor. In the above process, there is a large loss in the process of forming the excitation magnetic field in the rotor winding.

[0158] The permanent magnet synchronous motor uses permanent magnet for excitation, and the rotor magnetic field is completely generated by permanent magnet material, and there is no additional energy consumption in the process of generating excitation magnetic field. When it is applied to urban rail vehicle, the loss of the motor can be greatly reduced.

[0159] However, there is a long coasting section in the running process of urban rail vehicle, and the rotor will idle under the action of vehicle inertia in the coasting section. For asynchronous motor, as long as the excitation current of the stator and the rotor is disconnected, the stator and rotor magnetic field will disappear, thereby disconnecting the coupling between the stator and the rotor. For permanent magnet synchronous motor, in the process of rotor idling, the permanent magnet magnetic field of the rotor does not disappear, and the magnetic field will be coupled with the stator core, which will cause excessive iron loss in the stator core, thereby affecting the performance of the motor, which is not conducive to reducing the energy consumption of the whole power system.

[0160] The permanent magnet synchronous motor provided by the embodiments of the present application applied to the power system of urban rail vehicle is dedicated to solving the problem that the energy saving effect of urban rail vehicle is not good due to high iron loss under light load or no load condition.

[0161] The urban rail vehicle mentioned here can include subway train, light rail train, monorail train and tramcar, etc.

[0162] The permanent magnet synchronous motor comprises a rotor assembly and a stator assembly, the structure of the rotor assembly can be seen from FIG. 1, the rotor assembly 11 comprises a rotor core 11, permanent magnets 12 and a magnetic conducting block 13, and the specific structure of the rotor assembly 11 has been described in detail above, and will not be repeated here.

[0163] In the embodiment of the present application, the magnetic conducting block 13 is configured to be located at a first position close to the permanent magnet slot 111 when the vehicle is in the coasting operating condition, so as to reduce the iron loss of the permanent magnet synchronous motor 1 in the coasting operating condition.

[0164] According to the principle of minimum magnetic resistance, the magnetic field will be distributed along the direction of smaller magnetic resistance, when the magnetic conducting block 13 is located at the first position close to the permanent magnet slot 111, because the magnetic resistance thereof is much smaller than that of air, the rotor permanent magnet field will preferentially pass through the magnetic conducting block 13, so that the magnetic field is gathered into the magnetic conducting block 13, which reduces the air gap magnetic field strength of the rotor assembly 10.

[0165] When the permanent magnet field of the rotor assembly 10 is reduced, in the operating condition that the motor is being dragged, the coupling effect between the rotor assembly 10 and the stator assembly 20 is weakened, thereby reducing the iron loss of the motor.

[0166] The magnetic conducting block 13 in the embodiment of the present application is also configured to be located at a second position away from the permanent magnet slot 111 when the vehicle is in the traction operating condition. In this case, an air gap is formed between the magnetic conducting block 13 and the rotor core 11, the magnetic resistance of this position is larger, the permanent magnet field of the permanent magnet 12 will preferentially pass through the rotor core 11 with smaller magnetic resistance, at this time, the air gap magnetic field strength of the rotor assembly 10 can be improved. The magnetic coupling effect between the rotor permanent magnet field and the stator winding magnetic field is stronger, so that the permanent magnet synchronous motor can output larger torque, thereby ensuring the traction performance of the motor.

[0167] When the magnetic conducting block 13 is located at the second position as shown in FIG. 1, it can be seen from FIG. 2 that the magnetic field strength in the air gap between the magnetic conducting block 13 and the rotor core 11 is close to 0, the magnetic induction lines of the permanent magnet field of the permanent magnet 12 mostly point outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly 10, especially at the end of the core of the stator assembly 20. At this time, strong coupling is generated between the three-phase winding magnetic field and the rotor permanent magnet field, so that the rotor assembly 10 can output larger power, at this time, the motor has better traction performance.

[0168] When the magnetic conducting block 13 is located at the first position as shown in FIG. 3, it can be seen in combination with FIG. 4 that the magnetic induction lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the position of the magnetic conducting block 13, that is, the permanent magnetic field is gathered to the side away from the air gap, the magnetic field strength at the position of the magnetic conducting block 13 is the largest, and the magnetic field strength in the air gap is 0. When the motor is dragged to make the rotor assembly freely rotate, the interaction between the air gap magnetic field and the stator core 20 is weakened due to the small air gap magnetic field strength at this time, thereby reducing the iron loss of the motor.

[0169] That is, according to the above technical solutions provided by the embodiments of the present application, by arranging the adjustable magnetic conducting block in the rotor assembly of the permanent magnet synchronous motor, the position of the magnetic conducting block is adjusted according to the running conditions of the urban rail transit vehicle, so that the motor iron loss can be reduced and energy can be saved in the vehicle coasting condition; meanwhile, the traction performance of the motor can be ensured in the traction condition.

[0170] For the existing permanent magnet synchronous motor, the air gap magnetic field strength is determined by the permanent magnet in the rotor assembly, which is relatively difficult to adjust, which will lead to a narrow constant power range, especially in the case of high speed, the efficiency of the motor will be significantly reduced. When applied to urban rail transit vehicles, the problem of significant decline in traction performance will occur at high traction speed.

[0171] Therefore, in some embodiments of the present application, the magnetic conducting block 13 is further configured to move between the first position and the second position to adjust the magnetic field distribution of the rotor assembly 10 and increase the speed regulation range of the permanent magnet synchronous motor 1 when the speed of the vehicle is greater than the first speed threshold.

[0172] The foregoing FIGS. 1-4 only show the magnetic field distribution of the magnetic conducting block 13 at the two extreme positions of the first position and the second position, which respectively correspond to the minimum magnetic field and the maximum magnetic field, and the rotor assembly 10 can present different air gap magnetic field strengths when the magnetic conducting block 13 is arranged at any position between the first position and the second position.

[0173] The first speed threshold can be the vehicle speed when the permanent magnet synchronous motor operates at the rated speed, for example, it can be 60 km / h, 80 km / h or 100 km / h, etc., and the embodiments of the present application do not make specific limitations thereon, which can be determined according to the specific parameters of the driving and transmission mechanism of the traction system of the vehicle.

[0174] When the speed of the vehicle exceeds the first speed threshold, the permanent magnet synchronous motor will exceed the constant power range, resulting in a decline in traction performance. In this case, the position of the magnetic conducting block 13 can be adjusted, for example, it is moved from the second position to the direction close to the first position, the magnetic field distribution of the rotor assembly 10 is changed to achieve the purpose of field weakening and speed expansion.

[0175] In some embodiments, when the position of the magnetic conducting block is adjusted, the specific position of the magnetic conducting block can be determined according to the speed of the vehicle. For example, the specific position of the magnetic conducting block can be determined according to the difference between the current speed of the vehicle and the first speed threshold. The greater the difference, the farther the magnetic conducting block is from the second position, and vice versa.

[0176] According to the technical solution, the movable magnetic conducting block is used to realize field-weakening over-speed in a high-speed scenario, which can avoid the problems of cost and energy consumption increase caused by the technical solution of applying demagnetizing current to realize field-weakening over-speed in the related art.

[0177] The embodiment of the present application also provides a power system applied to an urban rail transit vehicle and used for providing power for the urban rail transit vehicle. The power system is also referred to as an electric transmission system of the urban rail transit vehicle, and the power system comprises the permanent magnet synchronous motor as described in any of the foregoing embodiments.

[0178] The embodiment of the present application also provides an urban rail transit vehicle comprising the permanent magnet synchronous motor or the power system as described in any of the foregoing embodiments. The urban rail transit vehicle can be a subway train, a light rail train, a monorail train, a tram, etc.

[0179] The embodiment of the present application also provides a permanent magnet synchronous traction motor, a traction system and a locomotive. The technical problems of the permanent magnet traction technology in the field of locomotives are solved.

[0180] The locomotive is an important tool for railway transportation and is used for traction or pushing of railway vehicles. The traction quality of the locomotive can usually reach several or dozens of times of the self. The technical solution provided by the embodiment of the present application is mainly applied to the traction locomotive of a freight train. For the freight train, the first problem to be considered is heavy load, that is, the maximum traction force (continuous traction force) needs to be exerted, and on this basis, the locomotive needs to be ensured to pass through a slope at a high speed (i.e., continuous speed), and the maximum speed of the locomotive, which is a performance of the rapid transportation capacity of the locomotive, must also be ensured.

[0181] According to the difference of power devices, the locomotive can be divided into a diesel locomotive and an electric locomotive.

[0182] The diesel locomotive usually takes a diesel engine or the like as a power source. The diesel engine is operated to drive a generator to operate. The electric energy generated by the generator is transmitted to an electric motor to convert the electric energy into mechanical energy. The mechanical energy is transmitted to a driving wheel of the locomotive through a transmission system such as a speed change gear to thereby traction the vehicle. The diesel locomotive is also referred to as an electric transmission diesel locomotive. The maximum power of the diesel locomotive is limited by the power of the diesel engine, which leads to the limitation of the traction capacity of the diesel locomotive.

[0183] The electric locomotive has fast starting and accelerating and strong climbing ability, is not affected by severe cold, and does not discharge exhaust gas during operation, and thus becomes the main force of modern railway transportation.

[0184] For electric locomotive, its traction motor and its control system constitute the most critical components of the electric drive system, which plays a decisive role in the performance of the whole vehicle. The development of electric drive system of electric locomotive has experienced DC drive, asynchronous drive and permanent magnet synchronous drive system.

[0185] Early locomotives widely use DC drive system. With the development of control technology, the speed regulation performance of AC asynchronous motor speed regulation system is improved by using field-oriented vector control technology, and the asynchronous motor itself has advantages, which has been widely used in the electric drive system of locomotive and has become the current mainstream.

[0186] Permanent magnet synchronous motor does not need rotor excitation current in operation, and has a series of advantages such as small size, low weight and high power density; it can output larger torque at low speed and has excellent low-speed performance; at the same time, China is rich in rare earth mineral resources, and the manufacturing cost of permanent magnet synchronous motor is low, so the application of electric drive system based on permanent magnet synchronous motor in locomotive has become one of the research hotspots in recent years.

[0187] As described above, the locomotive has the characteristics of low speed and heavy load, and its continuous running speed is generally 20-25km / h, and the maximum running speed is usually not more than 120km / h, which requires the electric drive system to output constant power in a wide speed range.

[0188] For permanent magnet synchronous motor, it can provide larger torque at low speed to ensure the low-speed traction performance of the locomotive; but the speed regulation range of this kind of motor is small, and in high-speed working condition, the working range of permanent magnet synchronous motor may exceed its constant power range, which will result in the inability to provide the required traction force in high-speed working condition, resulting in limited traction performance.

[0189] The permanent magnet synchronous traction motor provided by the embodiment of the application can ensure constant power output in a wide speed range and ensure the traction performance of the locomotive.

[0190] The permanent magnet synchronous motor includes a stator assembly and a rotor assembly, the rotor assembly includes a rotor core, a permanent magnet and a magnetic conducting block, see the description of the foregoing Fig. 1 and the foregoing description, and the specific structure of the rotor assembly will not be repeated here.

[0191] Referring to Fig. 1, in this embodiment, the magnetic conducting block 13 is configured to move between a first position close to the permanent magnet slot 111 and a second position away from the permanent magnet slot 111 according to the running speed of the locomotive, adjust the magnetic field distribution of the rotor assembly 10, so that the permanent magnet synchronous traction motor 1 outputs constant power when driving the locomotive to work in its running speed range.

[0192] The saturation magnetic induction of the magnetic conductive block 13 is much larger than air, and the magnetic resistance is smaller. The rotor permanent magnetic field will preferentially pass through the magnetic conductive block 13, and the magnetic field near the magnetic conductive block 13 is gathered. When the magnetic conductive block 13 moves between the first position and the second position, different influences are brought to the distribution of the rotor permanent magnetic field. Therefore, in the technical solution of the present application, the position of the magnetic conductive block can be adjusted according to the running speed of the locomotive, so as to change the magnetic field distribution of the rotor assembly, so that the permanent magnet synchronous traction motor can output constant power.

[0193] When the magnetic conductive block 13 is located at the second position as shown in FIG. 1, it can be seen from FIG. 2 that the magnetic field strength in the air gap between the magnetic conductive block 13 and the rotor core 11 is close to 0, and the magnetic induction lines of the permanent magnetic field of the permanent magnet 12 mostly extend outward, and the point with the maximum magnetic field strength is located in the air gap of the rotor assembly 10, especially at the end of the core of the stator assembly 20. At this time, the stator three-phase winding magnetic field is strongly coupled with the rotor permanent magnetic field, and the rotor assembly 10 can output larger torque, which is suitable for low-speed working conditions such as climbing or starting.

[0194] When the magnetic conductive block 13 is located at the first position as shown in FIG. 3, it can be seen from FIG. 4 that the magnetic induction lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the position of the magnetic conductive block 13, that is, the permanent magnetic field is gathered to the side away from the air gap, and the magnetic field strength at the position of the magnetic conductive block 13 is the largest, while the magnetic field strength in the air gap is close to 0. In this case, the magnetic conductive block 13 realizes the field weakening of the rotor assembly, and at this time the permanent magnet synchronous traction motor 1 can maintain the output power basically constant while rotating at high speed, which is suitable for the aforementioned high-speed running working condition.

[0195] It should be noted that the above only describes the case when the magnetic conductive block 13 is at the two extreme positions of the first position and the second position. When the magnetic conductive block 13 is located at different positions between the first position and the second position, the rotor assembly 10 will exhibit different magnetic field distributions; the closer to the first position, the smaller the permanent magnetic field strength of the rotor assembly 10, and the closer to the second position, the larger the permanent magnetic field strength. In actual application, the position of the magnetic conductive block 13 can be determined according to the speed of the locomotive, so that the traction motor can output constant power in the entire speed range.

[0196] According to the above technical solution provided by the present application, by arranging a movable magnetic conductive block in the rotor assembly of the permanent magnet synchronous traction motor, during the running of the locomotive, the position of the magnetic conductive block is adjusted according to the running speed of the locomotive, so as to change the magnetic field distribution of the rotor assembly, so that the permanent magnet synchronous traction motor can output constant power in the running speed range of the locomotive, and the traction capacity and running efficiency of the locomotive are improved.

[0197] In some embodiments, the magnetic conducting block 13 is further configured to be located at or close to the first position when the speed of the locomotive is greater than the first speed, so as to reduce the air gap magnetic field strength of the rotor assembly and increase the rotating speed of the permanent magnet synchronous traction motor. The first speed is related to the rated rotating speed of the permanent magnet synchronous traction motor.

[0198] The first speed can be the speed of the locomotive when the permanent magnet synchronous traction motor operates at the rated rotating speed, for example, can be 100 km / h or 120 km / h, etc. The embodiments of the present application do not make specific limitations thereon, and can be determined according to the specific parameters of the driving and transmission mechanism of the traction system of the locomotive. The smaller the first speed is, the narrower the demand for the constant power range of the permanent magnet synchronous traction motor is. When the speed of the locomotive exceeds the first speed, the traction motor can work outside the constant power range, which can cause the traction performance of the locomotive to decrease. In this case, the magnetic conducting block can be moved towards the first position to change the magnetic field distribution of the rotor assembly, so as to achieve the purpose of field weakening and speed expansion.

[0199] In the above technical solution, the movement of the magnetic conducting block is used to achieve the field weakening and speed expansion of the permanent magnet synchronous traction motor in the high speed working condition, so that the permanent magnet synchronous traction motor can maintain constant power output at high rotating speed, and the problems of cost and energy consumption increase caused by the existing technical solution of applying demagnetizing current for field weakening and speed expansion are avoided.

[0200] The embodiments of the present application further provide a traction system applied to a locomotive, which can be an electric transmission diesel locomotive or an electric locomotive. The traction system comprises the permanent magnet synchronous traction motor as described above.

[0201] The embodiments of the present application further provide a locomotive comprising the permanent magnet synchronous traction motor or the traction system as described above.

[0202] The locomotive can be an electric transmission diesel locomotive, for example, which is driven by an internal combustion engine to drive a generator to operate, and the generator sends out electric energy to the synchronous traction motor or the traction system to drive the vehicle. Alternatively, the locomotive can also be an electric locomotive, which can store electric energy by means of a battery or receive electric energy from a catenary by means of a pantograph. The permanent magnet synchronous traction motor or the traction system converts the received electric energy into mechanical energy to drive the vehicle.

[0203] The embodiments of the present application further provide a power system and a train, which are dedicated to solving the safety problem of the permanent magnet synchronous motor in the power system of the railway vehicle, especially the high speed railway vehicle, when an inter-turn short circuit fault occurs.

[0204] When a part or all of the permanent magnet synchronous motors in the train power system occurs a turn-to-turn short circuit fault, the train cannot stop immediately due to the huge inertia of the train. Especially for high-speed motor train unit trains and high-speed railway trains, when the running speed is 350 km / h, the braking distance is about 6500 meters; when the speed reaches 400 km / h, the braking distance will increase to 9100 meters.

[0205] In the above braking process, the motor in the train power system works in the reverse drag working condition, and the rotor in the motor is dragged to high-speed idle. Since the rotor assembly of the permanent magnet synchronous motor is excited by a permanent magnet, the rotor permanent magnet field does not disappear when the motor is idling; that is, the electromagnetic coupling between the stator and rotor assemblies has not been eliminated, and the stator winding cuts the permanent magnet field to generate a large circulating current in the stator winding.

[0206] The circulating current in the stator winding will cause the winding to heat, causing the temperature in the motor housing to rise sharply, which poses a risk of high-temperature demagnetization of the permanent magnet. At the same time, the temperature is too high to cause the winding to catch fire, and if the fire spreads in the high-speed moving motor train unit train, it will cause huge loss of life and property. The large short-circuit current in the stator winding will generate a pulsating magnetic field, which can interact with the rotor permanent magnet field, causing the motor to produce strong vibration, which in turn drives the car body to vibrate, which will threaten the safe operation of the high-speed motor train unit train. In addition, even if the train can stop quickly when a fault occurs, it needs to be towed back to the garage by other trains, and in this process, the turn-to-turn short circuit will still be further expanded, and there is still a risk of fire.

[0207] The power system provided by the embodiments of the present application can reduce the probability of occurrence of safety accidents when a turn-to-turn short circuit fault occurs in a permanent magnet synchronous motor, and realize fault-oriented safety. The power system is applied to a train, and the train can be any one of a general speed train, a fast train, a motor train unit train and a high-speed train, which is not limited by the embodiments of the present application.

[0208] The power system includes a plurality of permanent magnet synchronous motors for driving the train to run, and the permanent magnet synchronous motor includes a stator assembly and a rotor assembly, and the rotor assembly includes a rotor core, a permanent magnet and a magnetic conducting block. The structure of the rotor assembly can be referred to FIG. 1, which is not described here.

[0209] The magnetic conducting block 13 is configured to move to a first position close to the permanent magnet slot 111 and a second position away from the permanent magnet slot 111 to adjust the magnetic field distribution of the rotor assembly 10. When the magnetic conducting block 13 is located at the first position close to the permanent magnet slot 111, the rotor permanent magnetic field will gather to the position of the magnetic conducting block 13; or in other words, in the case that the magnetic conducting block is located at the first position close to the permanent magnet slot 111, the rotor permanent magnetic field does not pass through the air gap of the rotor assembly; or in other words, in the case that the magnetic conducting block is located at the first position close to the permanent magnet slot 111, the air gap magnetic field of the rotor assembly is 0. When the magnetic conducting block 13 is located at the second position away from the permanent magnet slot 111, an air gap is formed between the magnetic conducting block 13 and the rotor core 11, and the magnetic resistance of the position is large. The permanent magnetic field of the permanent magnet 12 will preferentially pass through the rotor core with smaller magnetic resistance, and at this time, the air gap magnetic field of the rotor assembly 10 has a larger magnetic field strength.

[0210] The power system in the embodiment of the present application is configured to: when an inter-turn short circuit fault occurs in a target permanent magnet synchronous motor in a plurality of permanent magnet synchronous motors, switch the magnetic conducting block in the target synchronous motor to the first position to short-circuit the main magnetic flux of the target permanent magnet synchronous motor, so that the target permanent magnet synchronous motor is taken out of service.

[0211] The plurality of permanent magnet synchronous motors in the power system in the embodiment of the present application, the target permanent magnet synchronous motor is the motor in which the inter-turn short circuit fault occurs, and the number thereof can be one or more, which is not limited in the embodiment of the present application.

[0212] The target permanent magnet synchronous motor can be determined according to the current or temperature of the stator winding of the plurality of permanent magnet synchronous motors in the power system. For example, during the operation of the power system, the current of the stator winding of the plurality of motors is monitored, and when the winding current of one or more motors abnormally increases, it can be determined that there is a risk of failure, and the motor can be determined as the target permanent magnet synchronous motor. According to the foregoing description, when the magnetic conducting block 13 is located at the first position, the rotor permanent magnetic field does not pass through the air gap of the rotor assembly, that is, in this case, the air gap magnetic field strength of the rotor assembly is close to 0. When the rotor assembly 10 is reversed and idles, due to the extremely low air gap magnetic field strength, the rotor assembly 10 will not generate a magnetic coupling effect with the stator winding, and therefore there will be no risk of circulating current, heating and vibration, etc., which can ensure the safety of the target permanent magnet synchronous motor.

[0213] According to the above technical means, in order to meet the requirement that the rotor magnetic field of the target motor that needs to be taken out of service during the operation of the train completely disappears, the movable magnetic conducting block in the rotor assembly is used to weaken the magnetic flux of the rotor assembly of the target motor, so that the target motor is taken out of service, thereby avoiding the impact on the safety of the train, and realizing failure-oriented safety.

[0214] The embodiment of the present application also provides a train comprising the power system as described above.

[0215] The embodiment of the present application also provides a permanent magnet synchronous motor and a mobile equipment, and the technical scheme is applied to the field of mobile equipment such as vehicles to solve the technical problems in the field.

[0216] The rotor magnetic field of the permanent magnet synchronous motor is generated by the permanent magnet in the rotor assembly, when the vehicle is in a high-speed working condition, the stator winding cuts the rotor magnetic field to generate a back electromotive force. When the back electromotive force rises, the motor will lose the ability to increase the speed, at this time, if you want to continue to increase the speed, you need to perform field weakening control on the rotor permanent magnetic field.

[0217] At present, the most commonly used field weakening method is to apply direct-axis field weakening current, which can reduce the back electromotive force in the stator winding and at the same time increase the motor speed. When performing field weakening control, the energy provided for the permanent magnet synchronous motor will be divided into two parts, one part is used to provide torque, and the other part is used for field weakening, which will increase the energy consumption and reduce the efficiency of the motor in the high-speed working condition.

[0218] The technical scheme provided by the embodiment of the present application can reduce the loss of the permanent magnet synchronous motor and improve its efficiency.

[0219] The permanent magnet synchronous motor provided by the embodiment of the present application is applied to a mobile device to provide power for the mobile equipment. The mobile equipment can be an electric vehicle using a permanent magnet synchronous motor as a power source, including land vehicles, air vehicles, water vehicles, industrial equipment, agricultural equipment or entertainment equipment, etc. For example, the water vehicle can be a hovercraft, a motorboat, a motorboat, a fishing boat, a cruise ship, a sailboat, a yacht, etc. The air vehicle can be an airplane, and the land vehicle can be a vehicle.

[0220] In some embodiments, the vehicle is a vehicle. For example, the vehicle is one of a commercial vehicle, a passenger vehicle, a motorcycle, a flying vehicle, a train.

[0221] In some embodiments, the vehicle is an industrial vehicle or an engineering vehicle. For example, the vehicle is one of a forklift, a trailer, a tractor, an excavator, a bulldozer, a crane, and an electric wheel mining truck.

[0222] In some embodiments, the vehicle can be an electric vehicle or a hybrid vehicle. Exemplarily, the vehicle can be one of a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range extended electric vehicle (REEV), and a plug-in hybrid electric vehicle (PHEV).

[0223] In some embodiments, the vehicle can also be an agricultural equipment (e.g., a mower, a harvester, etc.), a recreational equipment, a toy vehicle, etc.

[0224] The permanent magnet synchronous motor provided in the embodiments of the present application comprises a stator assembly and a rotor assembly. The structure of the rotor assembly can be referred to FIG. 1 and the foregoing description, which will not be repeated here.

[0225] The magnetic conducting block 13 is configured to move to the first position or close to the first position when the speed of the mobile equipment is greater than the first speed, so as to improve the efficiency of the permanent magnet synchronous motor in the high speed working condition.

[0226] It should be understood that the first speed is related to the inherent parameters of the permanent magnet synchronous motor applied in the mobile equipment. For example, the first speed can be determined according to the maximum speed of the permanent magnet synchronous motor in the constant power region; or the first speed can also be determined according to the rated speed of the permanent magnet synchronous motor. When the speed of the vehicle is greater than the first speed, it is considered to be in the high speed working condition.

[0227] It should be further understood that the first speed is usually different for different types of mobile equipment. For example, for a mine truck, in order to ensure a large traction capacity, the reduction ratio of the transmission mechanism is usually high, and the moving speed is usually slow, so the corresponding first speed is low, for example, it can be 15 km / h or 20 km / h, etc. For example, for an electric vehicle, the moving speed is usually fast, and the first speed can be 100 km / h, 120 km / h or higher.

[0228] When the speed of the mobile equipment is high, as described above, the efficiency of the demagnetizing current is low. In the technical solution of the present application, the permanent magnet magnetic field of the rotor assembly can be adjusted by using the movable magnetic conducting block described above, and the purpose of field weakening can also be achieved. Since this method does not need to provide a demagnetizing current, the part of energy is saved, thereby improving the energy efficiency of the permanent magnet synchronous motor.

[0229] As shown in FIG. 2, when the magnetic conductive block 13 is located at the first position, the magnetic induction lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the position of the magnetic conductive block 13, that is, the permanent magnetic field is gathered to the side away from the air gap, the magnetic field intensity at the position of the magnetic conductive block 13 is the maximum, and the magnetic field intensity in the air gap is 0.

[0230] The structure of the permanent magnet synchronous motor when the magnetic conductive block 13 is located at the second position and the corresponding magnetic field distribution are shown in FIG. 3 and FIG. 4, respectively.

[0231] As can be seen from FIG. 3 and FIG. 4, when the magnetic conductive block 13 is located at the second position, the magnetic induction lines of the permanent magnetic field of the permanent magnet 12 mostly extend to the outside, and the point with the maximum magnetic field intensity is located in the air gap of the rotor assembly 10, especially at the end of the core of the stator assembly 20. When the mobile equipment is normally operated, the magnetic conductive block 13 can be kept at this position to make the permanent magnet synchronous motor exert the maximum capacity to output constant power, so as to ensure the low-speed traction capacity and acceleration capacity of the vehicle.

[0232] It can also be understood that FIG. 1-FIG. 4 only show the magnetic field distribution when the magnetic conductive block 13 is located at the two extreme positions of the first position and the second position. Actually, the magnetic conductive block 13 can move between the two positions, and since the magnetic resistance of the magnetic conductive block 13 is much smaller than air, the rotor permanent magnetic field will move to the direction with smaller magnetic resistance, so when the position of the magnetic conductive block 13 changes, the magnetic field distribution of the rotor assembly 10 changes accordingly. The closer the magnetic conductive block 13 is to the first position, the smaller the air gap magnetic field intensity is, and vice versa, the closer the magnetic conductive block 13 is to the second position, the greater the magnetic field intensity is. Therefore, in the technical solution of the embodiment of the present application, in order to improve the efficiency under high-speed working condition, the magnetic conductive block 13 can be moved to the first position or close to the first position.

[0233] The embodiment of the present application also provides a mobile equipment comprising the permanent magnet synchronous motor as described above.

[0234] The embodiment of the present application also provides a permanent magnet synchronous motor and a vehicle, which are used to solve the safety problem caused by the large counter electromotive force when the permanent magnet synchronous motor rotates at high speed.

[0235] The rare earth permanent magnet with high magnetic field intensity is embedded in the rotor assembly of the permanent magnet synchronous motor, and when the rotor rotates, the magnetic flux through the coil of the stator winding will change greatly. According to the law of electromagnetic induction, the stator winding coil will generate an electromotive force because of the changing magnetic field, and the size of the electromotive force is proportional to the number of turns of the stator winding coil, the air gap magnetic field intensity and the rotation speed of the rotor. For the permanent magnet synchronous motor, the number of turns of the coil and the air gap magnetic field intensity are usually constant values, so the higher the rotation speed of the motor, the larger the counter electromotive force.

[0236] In order to ensure the performance of the permanent magnet synchronous motor at high speed, in the related art, a feasible method for reducing the back electromotive force is to weaken the rotor by applying a d-axis demagnetizing current to reduce the air gap magnetic field strength, thereby ensuring the performance of the motor at the current high speed, and the speed range of the motor operation can be increased.

[0237] However, the method of increasing the demagnetizing current causes high copper loss, which reduces the efficiency of the motor at high speed. Meanwhile, this method also requires additional components in the circuit part, which increases the cost of the whole machine.

[0238] The permanent magnet synchronous motor and the vehicle provided by the embodiments of the present application can suppress the back electromotive force of the permanent magnet synchronous motor at high speed, and expand the operating range of the permanent magnet synchronous motor. The technical solution is described in detail as follows.

[0239] The permanent magnet synchronous motor includes a stator assembly and a rotor assembly, and the rotor assembly includes a rotor core, a permanent magnet, and a magnetic conducting block. The structure of the rotor assembly is described with reference to FIG. 1 and the foregoing description, which is not repeated here.

[0240] In the embodiments of the present application, the magnetic conducting block 13 is configured to move from the second position to the direction close to the first position to reduce the back electromotive force of the stator assembly 20 when the back electromotive force of the stator assembly 20 increases.

[0241] When the back electromotive force increases, the magnetic conducting block 13 is moved to the direction close to the first position, which reduces the magnetic field strength of the rotor assembly 10. Under the same conditions, the back electromotive force will decrease with the decrease of the magnetic field strength.

[0242] It should be noted that in the technical solution of the embodiments of the present application, the increase of the back electromotive force of the stator assembly 10 can be determined by monitoring the voltage or current of the stator winding. Specifically, during the operation of the motor, the voltage or current of the stator winding is monitored in real time. The greater the change, the greater the back electromotive force. According to the above technical solution, by providing a movable magnetic conducting block in the rotor assembly of the permanent magnet synchronous motor, when the back electromotive force of the stator increases at high speed, the magnetic field strength of the rotor assembly is reduced by moving the magnetic conducting block, which can effectively suppress the back electromotive force of the stator assembly, so that the motor has higher power factor and efficiency at high speed, and the operating range of the motor is increased.

[0243] In some embodiments, when the magnetic conducting block 13 is located at the first position, the back electromotive force of the stator assembly 20 is 0.

[0244] As mentioned earlier, when the magnetic block 13 is in the first position, it can completely short-circuit the magnetic flux of the rotor assembly 10, making the magnetic intensity of the rotor assembly 10 zero. At this time, the magnetic coupling between the rotor assembly 10 and the stator assembly 20 is completely released, thereby making the back electromotive force of the stator assembly 20 zero. Therefore, there are no risks such as circulating current, heat generation, or vibration.

[0245] This application also provides a vehicle including a permanent magnet synchronous motor as described above. In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0246] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0247] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0248] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0249] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0250] The above is only a preferred embodiment of the present application, and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application. Industrial applicability

[0251] The embodiment of the present application provides a rotor assembly, a permanent magnet synchronous motor, a traction system and a vehicle. By arranging the magnetic conducting block corresponding to the plurality of permanent magnets in the rotor assembly, the different leakage magnetic fields are generated by adjusting the position of the magnetic conducting block, so that the adjustment of the permanent magnet magnetic field is realized, and the wide speed regulation range of the permanent magnet synchronous motor is ensured. The power factor and efficiency of the permanent magnet motor at high speed are improved, and the motor idling iron loss can be eliminated or reduced. When the magnetic conducting block is moved to the end close to the permanent magnet, the rotor permanent magnet magnetic field can be gathered in the rotor assembly, so that the larger counter electromotive force in the conductor of the motor when being counter-tracked can be avoided, and the safety of the traction system when the inter-turn short circuit of the stator winding occurs is ensured.

Claims

A rotor assembly, comprising: a rotor core having a plurality of permanent magnet slots distributed along a circumferential direction; a plurality of permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conductive blocks being arranged along a radial direction at a side of the corresponding permanent magnet slot close to a rotation axis; the magnetic conductive blocks are configured to move between a first position close to the permanent magnet slots and a second position away from the permanent magnet slots to adjust a magnetic field distribution of the rotor assembly. According to the rotor assembly of claim 1, when the magnetic conductive blocks are located at the first position, the magnetic conductive blocks abut against the rotor core at an end of the magnetic conductive blocks close to the permanent magnet slots along the radial direction. According to the rotor assembly of claim 2, the permanent magnet slots include a first permanent magnet slot and a second permanent magnet slot symmetrically arranged about a D-axis center line; a first opening is formed at an end of the first permanent magnet slot close to the rotation axis and an end of the second permanent magnet slot close to the rotation axis, a width of the magnetic conductive blocks along a direction perpendicular to the radial direction is not less than a width of the first opening, so that when the magnetic conductive blocks are located at the first position, an end face of the magnetic conductive blocks close to the permanent magnet slots can cover the first opening. According to the rotor assembly of claim 3, the rotor core has a recessed portion recessed toward a direction close to the permanent magnet slots, the recessed portion is arranged corresponding to the permanent magnet slots and located at a side of the permanent magnet slots close to the rotation axis; an end of the magnetic conductive blocks close to the permanent magnet slots has a protruding portion, the protruding portion matches a shape of the recessed portion, and when the magnetic conductive blocks are located at the first position, the protruding portion extends into the recessed portion. According to the rotor assembly of claim 4, the protruding portion is a circular arc-shaped end face. According to the rotor assembly of claim 4, the protruding portion includes a first end face and a second end face arranged in a V-shape, and an included angle formed by the first end face and the second end face is toward an end close to the permanent magnet slots. According to the rotor assembly of claim 6, the included angle formed by the first end face and the second end face is an obtuse angle. According to any one of claims 5-7, the rotor core has a plurality of sliding grooves arranged corresponding to the plurality of permanent magnet slots, each of the sliding grooves is arranged along a radial direction, a first end of the sliding groove along the radial direction is close to the permanent magnet slots, and a second end of the sliding groove is arranged away from a rotation axis of the rotor assembly, and the magnetic conductive blocks are slidable in the sliding grooves to move between the first position and the second position; the first end of the sliding groove has a recessed area, and the recessed area matches a shape of the protruding portion. According to the rotor assembly of claim 8, an arc angle of an end of the first permanent magnet slot and the second permanent magnet slot close to the rotation axis is less than or equal to an arc angle of an end of the first permanent magnet slot and the second permanent magnet slot away from the rotation axis. According to the rotor assembly of claim 9, the first position is located at an end of the first permanent magnet slot and the second permanent magnet slot close to the rotation axis. The rotor assembly according to claim 10, wherein two ends of the first permanent magnet slot are provided with a first magnetic isolation slot and a second magnetic isolation slot, and two ends of the second permanent magnet slot are provided with a third magnetic isolation slot and a fourth magnetic isolation slot. The rotor assembly according to claim 11, wherein the rotor core further has inner magnetic bridges corresponding to the permanent magnet slots, the inner magnetic bridges comprising a first inner magnetic bridge and a second inner magnetic bridge, the first inner magnetic bridge being located between the slide groove and the second magnetic isolation slot, and the second inner magnetic bridge being located between the slide groove and the fourth magnetic isolation slot. The rotor assembly according to claim 11, wherein the rotor core further has outer magnetic bridges corresponding to the permanent magnet slots, the outer magnetic bridges comprising a first outer magnetic bridge and a second outer magnetic bridge, the first outer magnetic bridge being located between the first magnetic isolation slot and an outer edge of the rotor assembly, and the second outer magnetic bridge being located between the third magnetic isolation slot and the outer edge of the rotor assembly. The rotor assembly according to claim 13, wherein the first magnetic isolation slot and the third magnetic isolation slot penetrate the rotor core in a radial direction. The rotor assembly according to claim 14, further comprising a rotor sheath sleeved outside the rotor core. The rotor assembly according to claim 15, wherein the rotor sheath is made of carbon fiber or non-magnetic alloy material. The rotor assembly according to claim 3, wherein the rotor core comprises a core shaft core, a D-axis core and a Q-axis core. wherein The core shaft core is a shaft sleeve close to the shaft center of the rotor core. The D-axis core is located between the first permanent magnet slot and the second permanent magnet slot. The Q-axis core is located between two adjacent permanent magnet slots. The core shaft core, the D-axis core and the Q-axis core are integrally formed according to claim 17. The core shaft core, the D-axis core and the Q-axis core are in a combined structure according to claim 17. The D-axis core is made of silicon steel material, amorphous material or nanocrystalline material. The Q-axis core is made of silicon steel material, amorphous material or nanocrystalline material. The core shaft core and the Q-axis core are integrally formed, or the Q-axis core and the core shaft core are connected through a dovetail structure according to claim 19. A permanent magnet synchronous motor comprising a rotor assembly and a stator assembly, the rotor assembly being any one of claims 1-20. A permanent magnet synchronous motor applied to a power system of a city rail transit vehicle, the vehicle power system comprising a plurality of permanent magnet synchronous motors for providing power for the vehicle, the permanent magnet synchronous motor comprising a rotor assembly and a stator assembly, the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conductive blocks corresponding to the plurality of permanent magnet slots, each magnetic conductive block being arranged on a side close to a rotation shaft of the corresponding permanent magnet slot in a radial direction; the magnetic conductive blocks being configured to: ​ The magnetic conducting block is located at a first position close to the permanent magnet slot when the vehicle is in the coasting mode, so as to reduce the iron loss of the permanent magnet synchronous motor in the coasting mode. The magnetic conducting block is located at a second position away from the permanent magnet slot when the vehicle is in the traction mode, so as to increase the air gap magnetic field strength between the rotor assembly and the stator assembly. The permanent magnet synchronous motor according to claim 22, The magnetic conducting block is further configured to move between the first position and the second position when the speed of the vehicle is greater than a first speed threshold, so as to adjust the magnetic field distribution of the rotor assembly and increase the speed regulation range of the permanent magnet synchronous motor. wherein The first speed threshold is related to the rated speed of the permanent magnet synchronous motor. A power system applied to an urban rail transit vehicle, for providing power for the vehicle, the power system comprising the permanent magnet synchronous motor according to claim 22 or 23. A vehicle for urban rail transit, the vehicle comprising: The permanent magnet synchronous motor according to claim 22 or 23, or the power system according to claim 24. A permanent magnet synchronous traction motor applied to a traction system of a locomotive, the permanent magnet synchronous traction motor comprising a rotor assembly and a stator assembly, the rotor assembly comprising: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conducting blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conducting blocks being arranged on a side close to a rotation shaft of the corresponding permanent magnet slot along a radial direction; The magnetic conducting block is configured to move between a first position close to the permanent magnet slot and a second position away from the permanent magnet slot according to the running speed of the locomotive, so as to adjust the magnetic field distribution of the rotor assembly and enable the permanent magnet synchronous traction motor to work at a constant power output when driving the locomotive to work within its running speed range. The permanent magnet synchronous traction motor according to claim 26, wherein the magnetic conducting block is further configured to: When the speed of the locomotive is greater than a first speed, the magnetic conducting block is located at or close to the first position, so as to reduce the air gap magnetic field strength of the rotor assembly and increase the speed of the permanent magnet synchronous traction motor, the first speed being related to the rated speed of the permanent magnet synchronous traction motor. A traction system applied to a locomotive, the traction system comprising the permanent magnet synchronous traction motor according to claim 26 or 27. A locomotive comprising: The permanent magnet synchronous traction motor according to claim 26 or 27, or the traction system according to claim 28. A power system applied to a train, the power system comprising a plurality of permanent magnet synchronous motors for driving the train to run, each of the permanent magnet synchronous motors comprising a rotor assembly and a stator assembly; The rotor assembly comprises: a rotor core having a plurality of permanent magnet slots uniformly distributed along a circumferential direction; permanent magnets arranged in the permanent magnet slots; a plurality of magnetic conducting blocks corresponding to the plurality of permanent magnet slots, each of the magnetic conducting blocks being arranged on a side close to a rotation shaft of the corresponding permanent magnet slot along a radial direction; A plurality of magnetic-conducting blocks are arranged corresponding to the plurality of permanent-magnet grooves, each of the magnetic-conducting blocks is arranged along a radial direction at a side of a corresponding permanent-magnet groove close to a rotating shaft, and the magnetic-conducting blocks are configured to switch between a first position close to the permanent-magnet grooves and a second position away from the permanent-magnet grooves to adjust a magnetic field distribution of the rotor assembly. The power system is configured to, in a case where an inter-turn short circuit fault occurs in a target permanent-magnet synchronous motor of the plurality of permanent-magnet synchronous motors, switch the magnetic-conducting blocks in the target permanent-magnet synchronous motor to the first position to short-circuit a main magnetic flux of the target permanent-magnet synchronous motor, and cause the target permanent-magnet synchronous motor to exit service. A train comprising the power system of claim 30. A permanent-magnet synchronous motor applied to a mobile equipment, the permanent-magnet synchronous motor comprising a stator assembly and a rotor assembly, the rotor assembly comprising: a rotor core having a plurality of permanent-magnet grooves distributed along a circumferential direction; permanent magnets arranged in the permanent-magnet grooves; a plurality of magnetic-conducting blocks arranged corresponding to the plurality of permanent-magnet grooves, each of the magnetic-conducting blocks is arranged along a radial direction at a side of a corresponding permanent-magnet groove close to a rotating shaft, and the magnetic-conducting blocks are configured to switch between a first position close to the permanent-magnet grooves and a second position away from the permanent-magnet grooves to adjust a magnetic field distribution of the rotor assembly. The magnetic-conducting blocks are configured to, when a speed of the mobile equipment is greater than a first speed, move to or close to the first position to improve an efficiency of the permanent-magnet synchronous motor in a high-speed working condition. A mobile equipment comprising the permanent-magnet synchronous motor of claim 32. A permanent-magnet synchronous motor comprising a stator assembly and a rotor assembly, the rotor assembly comprising: a rotor core having a plurality of permanent-magnet grooves distributed along a circumferential direction; permanent magnets arranged in the permanent-magnet grooves; a plurality of magnetic-conducting blocks arranged corresponding to the plurality of permanent-magnet grooves, each of the magnetic-conducting blocks is arranged along a radial direction at a side of a corresponding permanent-magnet groove close to a rotating shaft, and the magnetic-conducting blocks are configured to switch between a first position close to the permanent-magnet grooves and a second position away from the permanent-magnet grooves to adjust a magnetic field distribution of the rotor assembly. The magnetic-conducting blocks are further configured to, when a back electromotive force of the stator assembly increases, move from the second position to a direction close to the first position to reduce the back electromotive force of the stator assembly. A vehicle comprising the permanent-magnet synchronous motor of claim 34.

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